获取HashMap值的计数数量 [英] get count number of HashMap value
本文介绍了获取HashMap值的计数数量的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
使用此链接中的代码将文本文件内容加载到GUI:
Using the code from this link loading text file contents to GUI:
Map<String, String> sections = new HashMap<>();
Map<String, String> sections2 = new HashMap<>();
String s = "", lastKey="";
try (BufferedReader br = new BufferedReader(new FileReader("input.txt"))) {
while ((s = br.readLine()) != null) {
String k = s.substring(0, 10).trim();
String v = s.substring(10, s.length() - 50).trim();
if (k.equals(""))
k = lastKey;
if(sections.containsKey(k))
v = sections.get(k) + v;
sections.put(k,v);
lastKey = k;
}
} catch (IOException e) {
}
System.out.println(sections.get("AUTHOR"));
System.out.println(sections2.get("TITLE"));
如果input.txt的内容为:
In case of if contents of input.txt:
AUTHOR authors name
authors name
authors name
authors name
TITLE Sound, mobility and landscapes of exhibition: radio-guided
tours at the Science Museum
现在我想计算HashMap中的值,但sections.size()
计数存储在文本文件中的所有数据行.
Now I want to count the values in HashMap, but sections.size()
counting all data line stored in text file.
我想问一下如何计算项目,即sections
中的值v
?如何根据作者姓名获得编号 4 ?
I w'd like to ask how can I count the items, i.e. values v
in sections
? How can I get number 4, according to authors name?
推荐答案
由于AUTHOR具有1对多的关系,因此应将其映射到List
结构而不是String
.
Since the AUTHOR has a 1 to many relationship, you should map it to a List
structure instead of a String
.
例如:
Map<String, ArrayList<String>> sections = new HashMap<>();
Map<String, String> sections2 = new HashMap<>();
String s = "", lastKey="";
try (BufferedReader br = new BufferedReader(new FileReader("input.txt"))) {
while ((s = br.readLine()) != null) {
String k = s.substring(0, 10).trim();
String v = s.substring(10, s.length() - 50).trim();
if (k.equals(""))
k = lastKey;
ArrayList<String> authors = null;
if(sections.containsKey(k))
{
authors = sections.get(k);
}
else
{
authors = new ArrayList<String>();
sections.put(k, authors);
}
authors.add(v);
lastKey = k;
}
} catch (IOException e) {
}
// to get the number of authors
int numOfAuthors = sections.get("AUTHOR").size();
// convert the list to a string to load it in a GUI
String authors = "";
for (String a : sections.get("AUTHOR"))
{
authors += a;
}
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